Received: 23 March 2018
Accepted: 10 September 2018
First Online: 11 October 2018
Ethics approval and consent to participate
: The data used in this project are from de-identified data sets in the public domain and therefore exempt from Human Subjects Review.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.